Effective dielectric function modeling of inhomogeneous and anisotropic silver films

Abstract

The physical properties of vapor deposited films, upon growth at oblique incidence with respect to a substrate, display inhomogeneity and anisotropy. In order to describe the optical properties of such films, it is necessary to model the dielectric response of the film by means of a dielectric tensor using an effective medium theory to obtain its “effective” dielectric function. We have developed a method to model the optical response of such films by considering a three-phase system; air-anisotropic film-substrate. The principal components of the dielectric tensor of the film are obtained by using an Effective Medium Approximation (EMA). We compared our results with spectroellipsometric measurements (pseudo-dielectric function) of silver films deposited at oblique incidence on glass slides obtaining five microstructural energy independent parameters for the films. These results compare adequately with experimental data in the entire interval considered (1.5–5.0 eV).